This invention relates to cannulas and cannula assemblies for use with surgical instruments and/or for use in filtering gas.
During some medical procedures, e.g., laparoscopic and endoscopic surgery, a suitable gas is introduced into the abdominal cavity to inflate the abdomen, and this introduction of gas is commonly referred to as insufflation. The inflation of the abdomen separates the interior organs and provides an enlarged cavity within which to perform the surgery. Typically, one or more trocars (slidably disposed in a cannula or cannula sleeve) are used to puncture the abdomen, the trocar is withdrawn, and insufflation gas is passed through at least one of the cannula(s) to inflate the abdomen. One or more instruments involved in the procedure, e.g., a laparoscope, scalpel, laser, ultrasonic device (such as an ultrasonic tissue fragmentation device) and/or electrocautery device, can be inserted through the appropriate cannula(s) as needed.
Lasers, ultrasonic tissue fragmentation devices, and electrocautery devices are typically used for cutting of tissues and/or blood vessels. However, this cutting often produces xe2x80x9csmokexe2x80x9d (e.g., vapor and/or mist) that can cloud or obstruct the surgeon""s view of the operative site. During the surgical procedure, gas can be vented from the abdominal cavity and into the surrounding atmosphere through a port on the cannula, e.g., to clear the surgeon""s field of vision of smoke generated by the cutting instruments. The gas can be released multiple times (typically intermittently, upon opening and closing a valve on the port) during the procedure. Once surgery is completed, the gas used to inflate the cavity is vented from the abdominal cavity, and this release of gas (and associated smoke) is referred to as de-sufflation (or exofflation).
Smoke can contain toxic, odiferous, and otherwise undesirable material that, if released into the environment of the operating room, could expose the surgeon and the surgeon""s staff to a health risk. Additionally, the gas to be introduced into the abdominal cavity can include undesirable material such as particulate and/or microbial contaminants.
Attempts have been made to filter gas passed from or into the abdominal cavity of the patient using a filter attached to a fitting on the cannula. However, these device arrangements (i.e., an external filter attached to a cannula fitting) have suffered from a number of drawbacks. For example, some of these device arrangements are bulky and/or heavy, and can interfere with the ability to move in and around the surgical site. The combined weight of the cannula and filter can put strain on the incision and/or cause leakage of gas. The filters may become plugged, fail to remove sufficient undesirable material and/or may require a labor intensive effort (possibly requiring numerous steps) to attach and operate them. Special equipment (e.g., evacuators) may have to be utilized with the filters.
The present invention provides for ameliorating at least some of the disadvantages of the prior art. These and other advantages of the present invention will be apparent from the description as set forth below.
In accordance with an embodiment of the instant invention, a cannula assembly is provided comprising a housing having at least a first port and a second port, and defining a fluid flow path between the two ports, and a gas filter disposed in the housing, across the fluid flow path. Preferably, the housing includes a cannula sleeve wherein the sleeve comprises the second port, and the housing is arranged to allow a trocar and/or at least one surgical instrument to be removably passed through the second port. In accordance with the invention, the filter is adapted to filter gas passed from the first port to the second port and/or gas passed from the second port to the first port. Accordingly, the cannula assembly is suitable for use during insufflation and/or de-sufflation. If desired, different embodiments of the cannula assembly can be used for insufflation and de-sufflation.
In some embodiments, the housing is re-usable and the gas filter can be removed from within the housing and discarded, and a replacement filter can be inserted therein.
In another embodiment, a cannula is provided, comprising a housing comprising having a first port and a second port, and defining a fluid flow path between the first port and the second port, the housing further comprising a first portion attached to a second portion, the first portion having a larger inner diameter than the second portion, the second portion comprising a cannula sleeve, the sleeve having a first end proximal to the first portion, and a second end distal to the first portion, the second end comprising the second port, wherein the sleeve includes additional openings (e.g., two or more openings) between the first end and the second end, and the cannula also defines a fluid flow path between the first port and the additional openings. In an embodiment, the cannula includes a gas filter to provide a cannula assembly.
Methods for using the cannula assemblies and cannulas, and systems comprising the cannula assemblies and cannulas, are also provided.
In preferred embodiments of de-sufflation applications, the gas filter removes laparoscopic smoke and reduces odor as the gas passes through the cannula assembly to the exterior of the housing.
Embodiments of the cannula and cannula assembly are suitable for use at any desirable constant or variable gas flow rate, and de-sufflation can be carried out without attaching a vacuum system to the assembly. Preferably, the cannula assembly can be easily added to any suitable system (e.g., a system for use in laparoscopic surgery). In an embodiment, the assembly (that can be part of a system) allows one-handed gas flow adjustment.
Embodiments of the invention are particularly for use in surgical environments, especially for use in laparoscopic surgery, as they can allow the surgical procedure to be completed more quickly and/or cost efficiently, e.g., by reducing the amount of valuable surgeon-, nurse-, technician- and/or operating room-time needed for the procedure. Time savings are particularly advantageous, since, for example, as of 1999, studies have estimated the value of time in the operating room during laparoscopic surgery as in the range of from $20 per minute to $120 per minute, or more.
The following definitions are used in accordance with the invention.
Trocar. A trocar (sometimes referred to as a stylet or obdurator) comprises a pointed instrument, preferably for puncturing the wall of a body cavity.
Cannula. A cannula comprises a sleeve (tube) for insertion into a body cavity. The sleeve has a lumen, and during insertion, the lumen is typically occupied by a trocar. Typically, fluid (e.g., at least one gas) is passed through the cannula into and/or from the cavity after the trocar is removed from at least a portion of the lumen. The trocar can be removed from the cannula, and one or more other surgical instruments can be passed through the cannula and into the body cavity. In some embodiments, gas is passed through the cannula while a surgical instrument (e.g., other than a trocar) is in the cannula.
Cannula Assembly. A cannula assembly comprises a housing comprising a cannula, the housing having at least a first port and a second port, and defining a fluid flow path between the two ports, and at least one gas filter disposed in the housing, across the fluid flow path. Preferably, the housing includes a cannula sleeve wherein the sleeve comprises the second port, wherein at least a portion of the housing has an interior diameter and/or volume that is greater than the interior diameter and/or volume of the cannula sleeve. For example, the housing can include a larger portion suitable for containing one or more gas filters therein, wherein the housing is integrally attached to a narrower portion comprising the cannula sleeve. Typically, the larger portion includes a plurality of side walls (e.g., two sets of opposing walls) or a continuous side wall. The housing can include a top and/or bottom wall, and any of the walls can be in the form of a hinged and/or removable cover. Preferably, the larger portion of the housing includes at least one wall comprising the first port. The ports can include a plurality of openings (e.g., formed by a grid or a series of slits or perforations). In an embodiment, the cannula assembly includes a trocar, e.g., a cannula assembly includes a trocar equipped with a cannula.
The cannula assembly can include additional elements such as, but not limited to, at least one of a handle, one or more valves, one or more additional ports (e.g., a third port, and in some embodiments, at least a fourth port, and at least one of these ports can include a plurality of openings), one or more interior walls, one or more connectors, and at least one instrument sealing arrangement. Preferably, the cannula assembly includes at least one instrument sealing arrangement (e.g., comprising at least one of a gasket, seal, and valve such as a duckbill valve), that can be pliable, adapted to contact the instrument(s) used during the procedure and reduce or minimize the leakage of gas from the inflated body cavity.
In a preferred embodiment, the housing is arranged to allow a surgical instrument (such as, for example, at least one of a trocar, laparoscope, optic probe, scalpel, laser, ultrasonic device, electrocautery device, and camera) to be removably passed through the second port.
Gas Filter. A gas filter (preferably a smoke filter) comprises at least one gas filter element (preferably a smoke filter element) comprising a porous retentive element, i.e., at least one porous medium that retains at least one undesirable material such as at least one of microorganisms (e.g., bacteria), viruses, cells, body fluids, particulates, aerosols and liquid droplets, and allows at least a portion of the gas to pass through the retentive element, wherein the gas is depleted of at least some level of the undesirable material(s) as the gas passes through the filter. The retentive element can also retain or reduce the passage therethrough of other undesirable material such as at least one of benzene, hydrogen cyanide, formaldehyde, and toluene, and/or the element can reduce the passage of odor therethrough. The porous retentive element comprising at least one porous medium can comprise a fibrous web, a membrane, combinations thereof, a composite, and the like.
The gas filter element (and the porous medium) can have any suitable physical dimensions and typically will be in sheet, cylindrical and/or pleated form having opposing sides (e.g., a first side and an opposing second side, in relation to a fluid to be treated wherein at least a portion of the gas is passed through the element) with a central portion therebetween, wherein the pores in the porous medium will generally enable fluid communication between the two opposing sides (e.g., between the first and second sides) of the element. Typically, the gas filter element comprises at least one hydrophobic membrane (preferably a hydrophobic microporous membrane) and/or at least one hydrophobic fibrous medium, through which the fluid (e.g., gas) to be treated passes.
The gas filter can have any suitable pore structure, for example, a Dioctyl Phthalate (DOP) smoke penetration rating (for example, measuring the membrane efficiency by the Monodisperse DOP Smoke Test, e.g., as described in ASTM D 2986-95a), a pore size (for example, as evidenced by bubble point, or by KL as described in, for example, U.S. Pat. No. 4,340,479), a pore rating, or a pore diameter (e.g., when characterized using the modified OSU F2 test as described in, for example, U.S. Pat. No. 4,925,572). The gas filter can have a pore structure that is uniform, substantially uniform, or it can vary in a continuous, a discontinuous, or a stepwise manner. For example, a smoke filter can have a graded pore structure. In some embodiments, a gas filter includes a plurality of elements and/or layers wherein individual elements and/or layers have different pore structures, e.g., different pore ratings. For example, a gas filter can comprise a gas filter element having a plurality of layers wherein at least two layers have different pore ratings.
The gas filter (preferably, the smoke filter) can include additional elements, layers, or structures, which can also be membranes, or other porous media. For example, in some embodiments, the smoke filter can include additional components that have different structures and/or functions, e.g., at least one of prefiltration, odor-reduction, support, drainage, spacing and cushioning. The gas filter can also include, for example, at least one of an endcap, a core, and a frame.
In those embodiments wherein the cannula assembly includes a plurality of gas filters, e.g., one filter for insufflation gas, and another filter for de-sufflation gas, the filters can have different configurations (e.g., pore structures, effective filtration areas and/or different elements).
Smoke. As used herein, the term xe2x80x9csmokexe2x80x9d includes gas (e.g., the insufflation gas in the abdominal cavity, such as, for example, CO2), as well as some of the material and/or some of the by-products produced by the ablation of tissues and/or blood vessels (e.g., mist, aerosols and droplets). Smoke can include additional material, such as toxic, odiferous, and otherwise undesirable material (e.g., benzene, hydrogen cyanide, toluene, formaldehyde, carbon monoxide, viruses, bacteria, cells, and/or body fluids from diseased tissue of the patient). In some embodiments, smoke includes at least one of bacteria and viruses.